CVE WatchJul 23, 2026

CVE-2026-45251

A file descriptor can be closed while a thread is blocked in a poll(2) or select(2) call waiting for that descriptor. Because the blocked t

CVSS

7.8

High

EPSS

0.2%

KEV

—

Exploit Today

0-100

Published: May 21, 2026 · Last modified: Jul 23, 2026 · CWE-416

EPSS · 30d

0.2%EPSS · 30 days0.2%

2026-07-052026-08-02

Technical description

A file descriptor can be closed while a thread is blocked in a poll(2) or select(2) call waiting for that descriptor. Because the blocked thread does not hold a reference to the underlying object, this closure may result in the object being freed while the thread remains blocked. In this situation, the kernel must remove the blocked thread from the per-object wait queue prior to freeing the object. In the case of some file descriptor types, the kernel failed to unlink blocked threads from the object before freeing it. When the blocked thread is subsequently woken, it accesses memory that has already been freed resulting in a use-after-free vulnerability. The use-after-free vulnerability may be triggered by an unprivileged local user and can be exploited to obtain superuser privileges.

Official references

security.freebsd.orghttps://security.freebsd.org/advisories/FreeBSD-SA-26:19.file.asc

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-20473—

—

——0In display, there is a possible memory corruption due to use after free. This could lead to local escalation of privilege if a malicious actor has already obtained the System privilege. User interaction is not needed for exploitation. Patch ID: ALPS11019722; Issue ID: MSV-7759.19h CVE-2026-673007.5 HIG

25.5%

——8FreeRDP before 3.29.0 contains client-side heap use-after-free vulnerabilities in the async update message proxy for RAIL WINDOW_STATE_ORDER and NOTIFY_ICON_STATE_ORDER when AsyncUpdate is enabled. When a malicious or compromised RDP server sends crafted update orders, the message proxy shallow-copies structures containing nested parser-owned pointers (e.g., titleInfo.string, windowRects, visibilityRects, icon buffers). The parser frees those nested buffers after the callback returns, so the queued async message later dispatches stale pointers, potentially causing memory corruption or a client crash.5h CVE-2026-672997.5 HIG

25.5%

——8FreeRDP before 3.29.0 contains a client-side heap use-after-free in the async update message proxy for WINDOW_ICON_ORDER when AsyncUpdate is enabled (e.g. xfreerdp /async-update). In update_message_WindowIcon() a shallow CopyMemory() overwrites a freshly allocated lParam->iconInfo with the parser-owned windowIcon->iconInfo pointer. After the parser callback returns, update_recv_window_info_order() frees window_icon.iconInfo, but the queued async message still retains and later dispatches that stale pointer. A malicious or compromised RDP server sending a crafted RAIL Window Alternate Secondary Order with WINDOW_ORDER_ICON can trigger use-after-free, leading to memory corruption and client crash.5h CVE-2026-106857.6 HIG

7.9%

——2The Zephyr Bluetooth GATT client CCC-write response handler gatt_write_ccc_rsp() in subsys/bluetooth/host/gatt.c invoked the application's params->subscribe() callback after it had already called params->notify(conn, params, NULL, 0). Per the public GATT API, a notify callback with NULL data is the documented signal that the subscription has terminated and the bt_gatt_subscribe_params struct may be freed or reused by the application; calling subscribe() on the struct afterwards is a use-after-free, including an indirect call through the freed params->subscribe function pointer. The error branch is remotely (adjacent) reachable: a Zephyr device acting as a GATT client that calls bt_gatt_subscribe() can be driven into this ordering when a connected GATT server peer answers the CCC write with an ATT Error Response (the peer-supplied error code flows through att_error_rsp -> att_handle_rsp into gatt_write_ccc_rsp). For applications that free or recycle subscription parameters in their notification-termination handler, this results in memory corruption, a crash (denial of service), or potentially attacker-influenced control flow. The fix reorders the handler so the subscribe() callback runs before the terminating notify(NULL) in both the error and unsubscribe paths.3d CVE-2026-630358.1 HIG

44.0%

——13A heap use-after-free vulnerability in the TransferSubscriptions service in open62541 may allow an authenticated attacker to cause a denial of service or potentially execute arbitrary code.3d CVE-2026-54522—

2.1%

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